CN111656037A

CN111656037A - Method for restoring a friction brake system, industrial system and control system

Info

Publication number: CN111656037A
Application number: CN201880087750.3A
Authority: CN
Inventors: 丹尼尔·埃里克松; 乔治恩·约翰逊; 克拉斯·福斯伯格; 乔瑟夫·霍姆纳
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2018-02-21
Filing date: 2018-02-21
Publication date: 2020-09-11
Anticipated expiration: 2038-02-21
Also published as: US20200331152A1; US11660765B2; WO2019161890A1; CN111656037B; EP3755918B1; EP3755918A1

Abstract

A method of restoring a friction braking device (38) of an industrial installation (10, 20), the method comprising performing a restoring operation comprising at least one movement of a second component (42) of the industrial installation (10, 20) relative to a first component (44) of the industrial installation (10, 20) while engaging the braking device (38) to apply braking energy to the movement; monitoring an actual value related to the braking energy of the braking device (38) during a recuperation operation; and stopping the resuming operation when the actual value reaches at least one target value. An industrial apparatus (10, 20) is also provided.

Description

Method for restoring a friction brake system, industrial system and control system

Technical Field

The present disclosure relates generally to friction braking devices for industrial equipment. In particular, a method of restoring a friction braking device of an industrial device, and an industrial device including a braking device, are provided.

Background

Various types of industrial equipment include braking equipment. A common industrial apparatus including a brake apparatus, in addition to, for example, a workpiece positioner, a conveyor belt, and a motor unit, is an industrial robot. An industrial robot may comprise a plurality of links or axes, such as six or seven links. At each connection, one part is movable relative to the other part. Movement of the linkage is typically provided by a motor. The movement of the connecting member is accelerated or decelerated by adjusting the speed of the motor. During normal operation, the coupling can only be decelerated by the motor. However, each connection is usually equipped with a braking device to achieve a high braking torque, for example in the case of emergency braking. The braking device can also be used to support static loads on the attachment, for example in the case of a power loss, in the case of disengagement during long standstill of the servo, or in the case of an automatic operating mode. The braking device may be arranged inside the motor or elsewhere.

The braking devices are often subjected to a small amount of wear, since the connection is usually only stopped by the motor. The braking device engages when the attachment moves to become stationary. The performance of the brake device may be negatively affected by dust and oxidation on the surfaces of the brake device, such as the surfaces of the brake disc and/or the armature plate. Furthermore, the performance of the braking device may be negatively affected by other friction reducing factors, such as service life. One solution to restore the braking function is to replace the braking device. This is an expensive and time consuming obstacle.

US 9537431B 2 discloses a brake device configured to determine braking of a motor with a brake. The brake determination device includes a brake control section, a determination section, and a signal output section. The brake control component is configured to activate or release the brake. The determination means is configured to determine whether the brake is abnormal when the brake control means activates the brake. The signal output section is configured to output a signal relating to the abnormality of the brake after the brake control section releases the brake in a case where the determining section determines that the actuator is abnormal.

Disclosure of Invention

It is an object of the present disclosure to provide a simple and reliable method for improving or protecting the function of one or more friction brake devices of an industrial plant.

It is another object of the present disclosure to provide a controlled recovery of one or more friction braking devices of an industrial plant.

Another object of the present disclosure is to avoid the need to replace one or more friction braking devices of an industrial plant.

It is another object of the present disclosure to provide an industrial apparatus that addresses one, some, or all of the above objects.

According to one aspect, there is provided a method for restoration of a friction braking device of an industrial plant, the method comprising performing a restoration operation, the restoration operation comprising at least one movement of a second component of the industrial plant relative to a first component of the industrial plant while engaging the braking device to apply braking energy to the movement; during a recovery operation, monitoring an actual value related to the braking energy of the braking device, the actual value being independent of the speed of movement; and stopping the resuming operation when the actual value reaches at least one target value. It is explicitly disclosed that the actual value is independent of the speed of movement to exclude an anti-lock braking system (ABS). Furthermore, in this method, the brake device may be continuously engaged during movement, as compared to an ABS system. Furthermore, the ABS system itself is expressly excluded from the scope of the appended claims, but does not exclude that the claims cover methods involving a brake device with an ABS and/or an industrial device comprising a brake device with an ABS.

The method thus constitutes a way of wearing the brake equipment in a controlled manner. The method provides for the recovery of a malfunctioning or less functional brake device of the industrial device. Throughout this disclosure, the recovery operation may be referred to as a braking operation.

As soon as the actual value related to the braking energy reaches at least one target value, the recovery operation is stopped. Thus, it is possible to ensure that an appropriate amount of braking energy is applied. Too low a braking energy may result in an insufficient recovery of the braking device. Too high a braking energy may lead to unnecessary wear and damage of the braking device. The braking energy applied during the recovery operation may be controlled. Throughout this disclosure, the target value related to braking energy may alternatively be referred to as an energy parameter.

The method can be widely applied to industrial equipment. Non-limiting examples of industrial equipment according to the present disclosure include a workpiece positioner, a conveyor belt, a motor unit, and an industrial robot. These industrial devices also constitute industrial actuators. Accordingly, the industrial equipment according to the present disclosure may be constituted by an industrial actuator.

The method according to the disclosure may for example consist of a method of restoring a workpiece positioner, a conveyor belt, a motor unit and/or a friction brake device of an industrial robot. Industrial robots constitute industrial equipment and industrial actuators themselves. Each link of an industrial robot also constitutes an industrial device and an industrial actuator. The method may be performed with or without an applied load on the industrial equipment.

The first part and the second part may constitute two relatively movable parts of a link or a shaft of an industrial device, for example a proximal link part and a distal link part of a link of an industrial robot (or vice versa). The industrial equipment may comprise one or more joints, for example six or seven joints in the case of an industrial robot. The movement of the second part relative to the first part may be a rotational movement or a translational movement.

The restoring operation may include at least one first movement in a first direction of the second component relative to the first component when the braking device is engaged; and at least one second movement in a second direction of the second component relative to the first component opposite the first direction. The method also includes teaching a first position of a second component of the industrial equipment relative to the first component and a second position of the first component relative to the second component. In this case, the first movement may be constituted by a movement of the first position to the second position, and the second movement may be constituted by a return movement of the second position to the first position.

The first movement may be assisted by gravity and the second movement may be resisted by gravity when the braking device is disengaged. Thus, when engaging the brake device, the first movement may be constituted by a downward movement with reference to the direction of gravity and the second movement may be constituted by an upward movement with reference to the direction of gravity. In this way, gravity may be used to facilitate an increase in braking energy to the braking device and/or to enable the braking device to grind energetically. The movement assisted by gravity can be realized, for example, by a connection which can be rotated about a horizontal axis.

The braking device may be engaged during the second movement. It may be the case that the second part of some of the links of other industrial equipment of an industrial robot cannot be moved downwards or only slightly. In other words, some movement of the second component is not (or rarely) assisted by gravity. For example, in many industrial robots, the first link comprises a first link member rotatable about a vertical axis relative to a fixed base member. In these cases, the restoring operation may include moving the second component using a braking device engaged in the first direction and the second direction. The starting operation according to the present disclosure may be performed before each movement of the second component using the braking device engaged in the first and second directions.

The recovery operation may include a plurality of sequences of the first move and the second move. Thus, the second part may be moved repeatedly, e.g. alternately in the first and second direction, until the actual value reaches the target value.

The actual value and the at least one target value may be constituted by a temperature, a braking torque, a braking force, a braking energy, a braking power, a braking time, an angular distance of the second component relative to the first component, a translation distance of the second component, or a combination thereof. These actual values may be obtained or derived from, for example, functions for measuring the braking torque of the braking device, the position, movement and/or acceleration of the first and second components, one or more temperature sensors, etc. Each of these target values may satisfy a different speed (or varying speed) of movement. These target values are therefore independent of the speed of movement.

Each of the actual values and the at least one target value may comprise an energy value and a power value. In this case, both the energy value and the power value may be used to control the temperature and wear of the brake equipment. A higher power target value will give a higher temperature when more braking energy is generated in a shorter time.

The method also includes setting at least one target value. At least one target value may be set such that the recovery operation produces sufficient wear and/or temperature. If the brake device is contaminated with particles, the target temperature may be set such that carbonization, evaporation, absorption, etc. of unwanted particles is promoted. According to one example, the target temperature for the recovery operation may be set to 150 ℃ or higher. The oxide layer and the aged layer are generally easily removed. In these cases, a lower target temperature may be used for recovery operations. By setting at least one target value, the method can be optimized according to different recovery procedures, i.e. the method is flexible for different recovery scenarios.

The method may further comprise estimating a state of the brake device, and the setting of the at least one target value may be based on the estimation. The estimation may be based on historical operating data of the brake device and/or the industrial device. The method may therefore also include the function of tracking the total braking energy applied by each braking device of the industrial plant, i.e. during normal operation of the industrial plant. In this way, wear of the brake equipment can be supervised. The total braking energy may consist of the total energy used after a successful refurbishment or restoration of the braking device. The method may be performed again when it is determined that the braking device needs to be recovered based on the total braking energy. A reminder to perform the method may be issued. Thus, frequent engagement or frequent and extensive engagement of the brake device can be ensured.

The method may further include determining a free moving space in the environment of the industrial device; and performs a recovery operation in the free movement space. In this way, disturbances of obstacles in the environment of the industrial plant can be avoided.

The method may further include determining whether the state of the brake device satisfies an expected state after stopping the recovery operation; and if the determined state of the brake apparatus does not satisfy the expected state, the recovery operation is performed again. The method further comprises setting again at least one target value relating to the braking energy of the braking device if the determined state of the braking device does not meet the expected state. For example, a service engineer may make this determination with a test program, such as the "cyclic brake check" (CBC) currently available in some ABB robots. If the function of the brake device is acceptable, the industrial device can resume its normal operation. Otherwise, another round of recovery is initiated.

The method may further comprise performing a start-up operation prior to the restoring operation, the start-up operation comprising a start-up movement of the second part relative to the first part when the braking device is disengaged, such that the restoring operation is started when the second part is moved. The recovery operation can thus be started when the brake device is moved. The start-up operation thus provides a delay in the start of the recovery operation and "higher-than-allowable-torque" of the connection due to engagement of the brake device when the connection is fixed can be avoided. In this manner, initiation of a recovery operation may be facilitated.

According to another aspect, an industrial apparatus is provided, the industrial apparatus comprising a first component; a second member movable relative to the first member; and a braking device configured to apply braking energy to movement of the second component relative to the first component; wherein the industrial device is configured to: performing a recovery operation, the recovery operation comprising at least one movement of the second component relative to the first component when the braking device is engaged to apply braking energy to the movement; during the recovery operation, monitoring an actual value related to the braking energy of the braking device, the actual value being independent of the speed of movement; and stopping the resuming operation when the actual value reaches the at least one target value. The industrial device may be further configured to perform any method according to the present disclosure. The industrial installation according to this aspect may be constituted, for example, by a workpiece positioner, a conveyor belt, a motor unit and/or an industrial robot.

According to another aspect, there is provided a control system for an industrial apparatus, the industrial apparatus comprising a first component, a second component movable relative to the first component, and a braking device configured to apply braking energy to movement of the second component relative to the first component, the control system comprising a data processing apparatus and a memory storing a computer program, the computer program comprising program code which, when executed by the data processing apparatus, causes the data processing apparatus to perform the step of instructing the industrial apparatus to perform a recovery operation, the recovery operation comprising at least one movement of the second component relative to the first component to apply braking energy to the movement when the braking device is engaged; commanding the industrial plant to monitor an actual value related to the braking energy of the braking device during the recovery operation, the actual value being independent of the speed of the movement; and stopping the resuming operation when the actual value reaches at least one target value. The computer program may comprise program code which, when executed by data processing apparatus, causes the data processing apparatus to command the performance of any method according to the present disclosure.

Drawings

Further details, advantages and aspects of the disclosure will become apparent from the following examples taken in conjunction with the accompanying drawings, in which:

FIG. 1: schematically showing a side view of an industrial robot;

FIG. 2: the control system is schematically shown;

FIG. 3 a: a cross-sectional side view schematically showing the braking device in a disengaged state; and

FIG. 3 b: a cross-sectional side view of the brake apparatus in the engaged state is schematically shown.

Detailed Description

Hereinafter, a method of restoring a friction brake device of an industrial device and an industrial device including the brake device will be described. The same reference numerals will be used to refer to the same or similar structural features.

Fig. 1 schematically shows a side view of an industrial robot 10. The industrial robot 10 constitutes an example of an industrial apparatus according to the present disclosure. Non-limiting alternative types of industrial equipment according to the present disclosure include workpiece positioners, conveyor belts, and motor units.

The industrial robot 10 is exemplified as a seven-axis industrial robot, but the present disclosure is not limited to this type of robot. An industrial robot according to the present disclosure may comprise at least three axes.

The industrial robot 10 of this example comprises a base part 12, a tool 14 and a control system 16, such as a robot controller. The industrial robot 10 further comprises a first link member 18 distal to the base member 12 and rotatable at a first connection 20a about a vertical axis relative to the base member 12, a second link member 22 distal to the first link member 18 and rotatable at a second connection 20b about a horizontal axis relative to the first link member 18, a third link member 24 distal to the second link member 22 and rotatable at a third connection 20c about a horizontal axis relative to the second link member 22, a fourth link member 26 distal to the third link member 24 and rotatable at a fourth connection 20d relative to the third link member 24, a fifth link member 28 distal to the fourth link member 26 and rotatable at a fifth connection 20e relative to the fourth link member 26, a sixth link portion distal to the fifth link member 28 and translationally movable at a sixth connection 20f relative to the fifth link member 28 A member 30, and a seventh link element 32 at a distal end of the sixth link element 30 and rotatable relative to the sixth link element 30 at a seventh connecting member 20 g. The seventh linking member 32 includes an interface (not indicated) with the tool 14 attached thereto. A braking device according to the present disclosure may be provided at one, some or each of the connectors 20a-20 g. Further, each of the connectors 20a-20g (also referred to as "20") constitutes an industrial device according to the present disclosure.

Fig. 2 schematically shows an example of the control system 16 of the industrial robot 10 in fig. 1. The control system 16 includes a data processing device 34 (e.g., a central processing unit CPU) and a memory 36. The computer program is stored in the memory 36. The computer program may comprise code which, when executed by the data processing apparatus 34, causes the data processing apparatus 34 to command the performance of any method according to the present disclosure.

Fig. 3a schematically shows a cross-sectional side view of an example of a braking device 38. The brake device 38 of this example is a power-off brake, i.e., the brake device 38 stops or maintains a load when power is accidentally lost or intentionally disconnected.

The braking device 38 is used to apply braking energy to relative rotational movement about an axis of rotation 40 between the second component 42 and the first component 44. For example, in the case of a brake device 38 arranged in the second connecting part 20b of the industrial robot 10, the first part 44 may be formed by or rigidly connected to the first link part 18 and the second part 42 may be formed by or rigidly connected to the second link part 22. However, the braking apparatus according to the present disclosure is not limited to the power-off brake or the rotational brake.

The brake device 38 of this example includes a magnet 46 fixedly attached to the first component 44. The magnet 46 houses a coil 48. The magnet 46 and the coil 48 are annular and surround the second part 42. The brake apparatus 38 also includes an annular fixed plate 50 (i.e., fixed with respect to the first component 44) and a plurality of guide rods 52. The fixed plate 50 is held stationary relative to the magnet 46 by guide rods 52.

The brake device 38 further comprises an annular rotatable friction brake disc 54. The brake disc 54 is connected to the second component 42 via a hub 56. The brake device 38 further comprises an annular armature plate 58, which is guided parallel to the rotational axis 40 by means of the guide rods 52, and a plurality of resilient elements 60, here realized as compression springs. The resilient element 60 is compressed and exerts a force on the armature plate 58 against the brake disc 54.

In fig. 3a, the brake device 38 assumes a disengaged state. A current is applied to the coil 48 so that a magnetic field is generated. The magnetic field attracts the armature plate 58 to the magnet 46 against compression of the resilient member 60. An air gap 62 is thus established between the brake disc 54 and the armature plate 58. In this state, the brake disc 54 will also lose the pressing contact with the fixed plate 50 because the brake disc 54 is allowed to move slightly axially.

Fig. 3b schematically shows a sectional side view of the brake device 38 in the engaged state. In the engaged state, no current is applied to the coil 48, and no magnetic field is generated. The resilient element 60 urges the armature plate 58 into engagement with the brake disc 54, thereby generating frictional braking energy.

An example of a method of recovery of the friction brake device 38 according to the present disclosure will now be described. Many of the steps in this example are optional and the method is limited only by the claims.

As a first step, the status of one or more brake devices 38 of the industrial robot 10 (or other industrial devices) may be estimated. In other words, it may be determined whether any of the brake devices 38 require recovery. This determination may be completely manual (e.g. based on detection by a service engineer) or automatic (e.g. based on historical operating data of the brake device 38 and/or the industrial robot 10). For example, the control system 16 may be provided with functionality to track the total braking energy applied by each braking device 38. Based on this function, it can be determined whether the braking device 38, to which no braking energy or only a small amount of energy is applied, needs to be recovered.

A target value relating to the braking energy of the brake arrangement 38 may then be set. The setting of the target value may be based on an estimated state of the brake device 38, for example based on a function of the total brake energy tracked by the brake device 38, or based on a manually estimated state. If the brake device 38 is not used at all for a period of time, then a certain state of the brake device 38 may be assumed. If the brake device 38 is used only to a lesser extent, another state of the brake device 38 may be assumed, and so on. Other parameters may also be considered to estimate (automatically or manually) the state of the brake device 38, such as air humidity, air pollution level and temperature in the environment of the industrial robot 10. The target value may be set manually or automatically. Alternatively, a predefined target value may be used.

Various types of target values relating to braking energy are possible. Examples of target values include a target temperature (measured or calculated), a target braking torque, a target braking force, a target braking energy, a target braking power, a target braking time, a target angular distance of the second component 42 relative to the first component 44, and the like, and any combination thereof. For some restoration processes, it may be desirable to obtain a certain temperature at the armature plate 58 and the brake disc 54. In this case, the target temperature value may be used. Alternatively, an energy target value may be used in combination with a power target value. For some recovery procedures, the target braking force may be more appropriate, optionally in combination with the target braking time.

The free movement space in the environment in which the industrial robot 10 is used for the restoration operation is then optionally determined so that the connecting elements get enough space for movement. In this way, a larger range of movement for the recovery operation may be allowed while avoiding collision with surrounding objects or the industrial robot 10 itself.

At least one first movement of the second component 42 relative to the first component 44 may then be determined. This first movement may be planned ahead of time, automatically determined by the robot (e.g., based on free moving space determination), or specifically planned when the recovery process is to be performed (e.g., by manually teaching the first and second locations).

Then, a recovery operation of the brake device 38 can be performed. The restoration operation includes at least one first movement of the second component 42 relative to the first component 44, engaging the braking device 38 such that braking energy is applied to the movement. The restoration operation may include a second return movement that engages or disengages the brake device 38. During the recovery operation, an actual value related to the braking energy of the brake device 38 is monitored. Thus, controlled wear of the brake device 38 is generated to accomplish the required recovery. It is explicitly disclosed that the actual value is independent of the moving speed (i.e. independent of the moving speed) to exclude ABS systems.

The applied braking energy may also be controlled during a recovery operation. In this way, the temperature rise during the recovery operation can be determined. Too high a braking power may result in too high a local temperature rise in the brake equipment 38.

To facilitate the initiation of the restore operation, the initiation operation may be performed prior to the restore operation (e.g., prior to the first move). The initiating operation may include accelerating the second member 42 from a standstill relative to the first member 44 to a target speed. Once the target speed is reached, a recovery operation is initiated. In this way, initiation of the recovery operation is facilitated, i.e. when engaging the braking device 38, the motor of the coupling requires a lower torque to move the second part 42 than from rest. The recovery operation is initiated after a time limit for the second member 42 to accelerate from rest relative to the first member 44, rather than when the target value is reached.

The first movement of the second member 42 relative to the first member 44 may be a downward movement assisted by gravity when the brake is engaged. For example, in case a restoration process is to be performed with respect to the brake device 38 associated with the third connection 20c of the industrial robot 10, the third link element 24 (here constituting the second part 42) may be rotated downwards with respect to the second link element 22 (here constituting the first part 44) upon engaging the brake device 38. This braking is stronger due to the gravitational force acting on the third link member 24 (and on the distal end portion of the third link member 24). The second movement may then consist of an upward movement of the third link element 24 relative to the second link element 22 when the brake device 38 is disengaged.

For the restoration of the braking device 38 associated with the first link 20a, i.e. between the first link element 18 (here constituting the second element 42) and the base element 12 (here constituting the first element 44), the first movement may be constituted by a rotation of the first link element 18 in a first direction about a vertical axis, and the second movement may be constituted by a rotation of the first link element 18 in an opposite second direction about a vertical axis. In this case, the brake device 38 may be engaged during the first movement and engaged during the second movement. Further, the start-up operation may be performed before each movement in the first direction and before each movement in the second direction.

In any case, the recovery operation may include a plurality of sequences of the first move and the second move. The recovery operation is stopped as soon as the actual value related to the braking energy reaches at least one target value. The stopping may occur first during the first movement, or during any subsequent movement, such as after some sequence of first and second movements.

Once the recovery operation is stopped, it can be determined whether the state of the brake device 38 satisfies the expected state. If this is the case, normal operation of the industrial robot 10 can be continued. If not, a further recovery operation is optionally performed by setting a new target value relating to the braking energy of the brake arrangement 38.

While the present disclosure has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the foregoing description. For example, it should be understood that the dimensions of the components may be varied as desired. Accordingly, the invention is not to be restricted except in light of the attached claims.

Claims

1. A method for restoration of a friction braking device (38) of an industrial device (10, 20), the method comprising:

-performing a recovery operation comprising at least one movement of a second part (42) of the industrial equipment (10, 20) relative to a first part (44) of the industrial equipment (10, 20) while engaging the braking device (38) to apply braking energy to the movement;

-during the recovery operation, monitoring an actual value related to the braking energy of the braking device (38), the actual value being independent of the speed of the movement; and

-stopping the recovery operation when the actual value reaches at least one target value.

2. The method of claim 1, wherein the recovery operation comprises:

-at least one first movement in a first direction of the second component (42) relative to the first component (44) upon engaging the braking device (38); and

-at least one second movement in a second direction of the second part (42) relative to the first part (44), opposite to the first direction.

3. The method of claim 2, wherein the first movement is assisted by gravity, and wherein the second movement is resisted by gravity upon disengagement of the braking device (38).

4. The method of claim 2, wherein the braking device (38) is engaged during the second movement.

5. The method of any of claims 2 to 4, wherein the recovery operation comprises a plurality of sequences of the first move and the second move.

6. The method according to any of the preceding claims, wherein the actual value and the at least one target value consist of temperature, braking torque, braking force, braking energy, braking power, braking time, angular distance of the second component (42) relative to the first component (44), translational distance of the second component (42), or a combination thereof.

7. The method according to any of the preceding claims, wherein each of the actual values and the at least one target value comprises an energy value and a power value.

8. The method of any of the preceding claims, further comprising: setting the at least one target value.

9. The method of claim 8, further comprising: estimating a state of the brake device (38), and wherein the setting of the at least one target value is based on the estimation.

10. The method according to claim 9, wherein the estimation is based on historical operating data of the brake device (38) and/or the industrial device (10, 20).

11. The method of any preceding claim, further comprising:

-determining a free moving space in the environment of the industrial equipment (10, 20); and

-performing said recovery operation in said free movement space.

12. The method of any preceding claim, further comprising:

-determining whether the state of the brake device (38) meets an expected state after stopping the recovery operation; and

-if the determined state of the brake device (38) does not satisfy the expected state, performing the recovery operation again.

13. The method of any preceding claim, further comprising:

-performing an activation operation before the restoration operation, the activation operation comprising an activation movement of the second part (42) relative to the first part (44) upon disengagement of the braking device (38), such that the restoration operation is activated upon movement of the second part (42).

14. An industrial plant (10, 20) comprising:

-a first component (44);

-a second part (42) movable relative to the first part (44); and

-a braking device (38) configured to apply braking energy to the movement of the second component (42) relative to the first component (44);

wherein the industrial device (10) is configured to:

-performing a restoring operation comprising at least one movement of the second component (42) relative to the first component (44) when engaging the braking device (38) to apply braking energy to the movement;

15. The industrial equipment (10, 20) according to claim 14, wherein the industrial equipment (10, 20) is an industrial robot (10).